Microfluidics is concerned with microstructural devices and systems with fluidic functions. This may involve the manipulation of very small quantities of fluid, i.e. liquid or gas, in the order of microliters, nanoliters or even picoliters. Important applications lie in the field of biotechnology, chemical analysis, medical testing, process monitoring and environmental measurements. A more or less complete miniature analysis system or synthesis system can herein be realized on a microchip, a so-called ‘lab-on-a-chip’ or, in specific applications, a so-called ‘biochip’. The device or the system can comprise microfluidic components such as microchannels, microtunnels or microcapillaries, mixers, reservoirs, diffusion chambers, pumps, valves and so forth.
The microchip is usually built up of one or more layers of glass, silicon or a plastic such as a polymer. Glass in particular is very suitable for many applications because of a number of properties. Glass has been known for many centuries and there are many types and compositions readily available at low cost. In addition, glass is hydrophilic, chemically inert, stable, optically transparent, non-porous and suitable for prototyping; properties which are in many cases advantageous or required.
In determined applications a microchip has to be connected to one or more reservoirs or wells. For this purpose the reservoirs are for instance manufactured separately and then, for instance by means of glueing or clamping, arranged on the microchip at the position of fluidic inlets or outlets arranged for this purpose in the ‘upper surface’ of the microchip, for example EP-A-1 424 559, EP-A-1 520 838, WO-A-2006/072 405, US-A-2005/176 059 and WO-A-01/09 598. The drawback is that the reservoirs and the possible seals occupy a relatively large part of the ‘upper surface’ of the microchip, thereby limiting the maximum density of inlets and outlets and the compactness of the device. In addition, the reservoirs and the possible seals may be ‘in the way’ during visual inspection or for instance during optical, electrical or other measurements. Wells are sometimes also arranged directly in the ‘upper surface’ of the microchip, generally as powder-blasted or drilled holes. The above stated drawbacks then also apply, and furthermore the additional process of powder-plastering or drilling is then necessary. The volume of the reservoirs is moreover limited by the low height of the reservoirs, in principle a maximum of the thickness of the microchip, as a result of the character of the microchips, which is by definition planar.
There is therefore a need for a solution, which does not have the above stated drawbacks, for the connection of one or more fluidic components, in particular reservoirs or wells, to one or more fluidic inlets or outlets of a microfluidic device or system. The invention has for its object to fulfil this need.